RE: [RFC PATCH v2 3/5] scsi: ufs: Introduce HPB module

Avri Altman
2020-06-18T06:19:55Z

>
> > > > implemented
> > > > > as a module parameter, so that it can be configurable by the
> > > > > user.
> > > > >
> > > > > To gurantee a minimum memory pool size of 4MB:
> > > > > $ insmod ufshpb.ko ufshpb_host_map_kbytes=4096
> > > >
> > > > You are going through a lot of troubles to make it a loadable
> > > > module.
> > > > What are, in your opinion, the pros and cons of this design
> > > > decision?
> > >
> > > In my opinion...
> > >
> > > pros:
> > > 1. A user can unload an unnecessary module when there is an
> > > insufficient
> > > memory situation (HPB case).
> > > 2. Since each UFS vendor has a different way of implementing UFS
> > > features,
> > > it can be supported as a separate module. Otherwise, many quirks must
> > > be attached to module, which is not desirable way.
> > > 3. It is possible to distinguish parts that are not necessary for
> > > essential
> > > ufs operation.
> > > 4. It is advantageous to implement the latest functions according to
> > > the
> > > development speed of UFS.
> > >
> > > cons:
> > > 1. It is difficult work to be implemented as a module.
> > > 2. Modifying "ufsfeature.c" is required to implement the feature that
> > > can
> > > not supported by the exsiting "ufsf_operation".
> > >
> > > Thanks,
> > > Daejun
> >
> > Dear Avri, Daejun, Bart
> >
> > It is true that it is very difficult to make everyone happy.
> > We now have three HPB drivers in the patchwork, but I still didn't see
> > a final agreement. Please tell me which one do you want to focus on?
> The HPB driver has been greatly improved in the process of being applied to
> mobile devices since the release of the first HPB version in openMPDK. We
> want to contribute to the linux mainline with the knowledge obtained
> through the experience.
> I find it difficult to make everyone happy, but I think it is possible that
> everyone can accept the HPB driver through several revisions.
Ack on that.
For me, it was very clear that Bart prefers the Samsung approach,
Hence I withdrew from my RFC and switch to support Daejun's.

Thanks,
Avri